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Author Topic:   bumpsteer
Dirt Roller

Total posts: 10
posted February 19, 2002 10:27 AM
how important is this on a modified,do many
guys mess with this. were can I get clear
easy understanding on how to set this

Dirt Maniac

Total posts: 183
posted February 19, 2002 06:40 PM
Its not critical, but you should have an idea of whats going on with the front end. With a straight axle (think sprint car) when a wheel goes over a bump, both wheels stay on the same toe setting, because they are hooked to the same piece of iron axle and tie rod. On a car with A frames, when a wheel goes over a bump, it can deflect, causing toe-in or toe out. In extream caes while moving it can cause both in the same bump. What is ideal is to have the thing bounce up and down, and not change the toe setting. Your chances are slim to none of getting it perfect. You can get it pretty close in a 3" range of tire travel (bump).
With your car at ride settings, front tires, springs, and shocks removed. Clamp a 4' piece of angle iron to the rotor, with the other end towards the front, on the floor. Put a mark where the iron meets the floor. Now jack the lower Arm up 3" while watching the iron piece move along the floor. If it went straight back your bump is perfect, if it moved about 1/8" out its great. In reality it made an S move or went in. If so that is what you need to correct. Dont worry about lots of up and down with the wheel through its entire range, if your wheel moves more than that you'll be so out of shape bump steer aint gonna save ya. Good luck

Dirt Forum Racer

Total posts: 82
posted February 20, 2002 07:05 PM
Gene, thanks for the idea on checking the bump. It's not very scientific, but I'm sure it will work just fine for seeing what's going on in the front end. Your idea is so simple, I can't believe I haven't thought about doing that.

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